Single inductor power converter system and methods

ABSTRACT

Methods, systems, and devices are described for a non-isolated dc-dc power converter that uses a single magnetic element and provides both a positive and a negative voltage output. The magnetic element, such as an inductor, is coupled with two or more switching modules that electrically switch the inductor to and from a voltage source, an inductor terminal, and/or a load. By electrically connecting and electrically isolating different components at various times, separate positive and negative voltage outputs are provided using the single inductor element. Switching may be controlled by a controller module, and a magnitude of the dc output voltage may be selected based on two or more resistors coupled with the controller module.

CROSS REFERENCES

This application claims priority to U.S. provisional patent application Ser. No. 61/370,444 entitled “AUTO-OPTIMIZATION CIRCUITS AND METHODS FOR CYCLICAL ELECTRONIC SYSTEMS,” filed on Aug. 3, 2010, the entire disclosure of which is incorporated herein by reference for all purposes. This application is also related to: U.S. patent application Ser. No. ______, filed on even date herewith, entitled “AUTO-ADJUSTMENT CIRCUITS AND METHODS FOR CYCLICAL ELECTRONIC SYSTEMS,” and referenced as Attorney Docket No. P026.01 (77702.0066); and U.S. patent application Ser. No. ______, filed on even date herewith, entitled “GATE DRIVER POWER AND CONTROL SIGNAL TRANSMISSION CIRCUITS AND METHODS,” and referenced as Attorney Docket No. P026.02 (77702.0070), and the entire disclosure of each is incorporated herein by reference for all purposes.

BACKGROUND

The present disclosure is directed to circuits and methods for providing dc power to two or more loads, and more specifically to circuits and methods for providing both positive and negative voltage outputs utilizing one inductor in the voltage converter.

Non-isolated dc-dc converters enable efficient designs for various applications. Such dc-dc converters receive an input voltage from an input power supply, and provide a power output at a voltage level that is different than the voltage of the input power supply. In cases where the output voltage is higher than the input voltage, capacitors and one or more inductors may be utilized to provide additional voltage, commonly employing one or more switches that switch various components within the dc-dc converter that result in energy being stored in the inductor(s) and/or capacitor(s).

Such dc-dc converters may be advantageously implemented in a number of different applications. For example, non-isolated dc-dc power converters may provide relatively high peak current demands and low noise margins for applications servicing high-performance semiconductor devices. By placing individual de sources near their point of use, voltage drops may be reduced, noise sensitivity may be reduced, and EMI emission issues may be reduced. Furthermore, placing individual dc sources near their point of use may provide for efficient regulation of voltage output under dynamic load conditions. Such non-isolated dc-dc converters may be used in various applications, such as providing power for semiconductor devices such as processors, memory, FPGAs, DSPs and ASICs, as well as standard digital and analog integrated circuits. Such non-isolated dc-dc converters commonly provide output power within a set voltage range to an output.

SUMMARY

Methods, systems, and devices are described for a non-isolated dc-dc power converter that uses a single magnetic element and provides both a positive and a negative voltage output. The magnetic element, such as an inductor, is coupled with two or more switching modules that electrically switch the inductor to and from a voltage source, an inductor terminal, and/or a load. By electrically connecting and electrically isolating different components at various times, separate positive and negative voltage outputs are provided using the single inductor element. Switching may be controlled by a controller module, and a magnitude of the dc output voltage may be selected based on two or more resistors coupled with the controller module.

In one embodiment, a power converter apparatus is provided. The power converter apparatus comprises a power source, a first switching module coupled with the power source, and an inductor having a first connection terminal and a second connection terminal, the first connection terminal coupled with the first switching module. The apparatus includes a first output terminal coupled with a first load. A second switching module is coupled with the first switching module and the first connection terminal of the inductor. A second output terminal is coupled with a second load. A control module is coupled with the first and second switching modules. The control module is configured to: switch the first switching module to electrically couple the first connection terminal of the inductor with the power source and thereby supply a positive voltage with the first output terminal; switch the first switching module to electrically isolate the power source from the first connection terminal of the inductor; and switch, while the power source is electrically isolated from the first connection terminal, the second switching module to electrically couple the first connection terminal of the inductor with the second output terminal and thereby supply a negative voltage to the second output terminal.

In another embodiment, a method is disclosed for providing power to a first and a second output load. The method comprises electrically coupling a first inductor connection terminal with a power source, electrically coupling the first output load with a second inductor connection terminal, and electrically isolating the second output load from the first inductor connection terminal while the first inductor connection terminal is electrically coupled with the power source. After electrically coupling the first inductor connection terminal with the power source, the method provides for electrically isolating the first inductor connection terminal from the power source and electrically coupling the first inductor connection terminal with the second output load.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the present invention may be realized by reference to the following drawings. In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.

FIG. 1 illustrates a system block diagram for an exemplary non-isolated dc-dc converter.

FIG. 2 illustrates a system block diagram for another exemplary non-isolated dc-dc converter.

FIG. 3 illustrates a circuit diagram for an exemplary switching module.

FIG. 3A illustrates a circuit diagram for another exemplary switching module.

FIG. 4A illustrates a block diagram for an exemplary switching module having a voltage sensor.

FIG. 4B illustrates a circuit diagram for another exemplary switching module having a voltage sensor.

FIG. 5 illustrates a block diagram for an exemplary controller module.

FIG. 6 illustrates a block diagram for another exemplary controller module.

FIG. 7 illustrates a block diagram for an exemplary voltage adjustment module.

FIG. 8 is a flow chart diagram illustrating the operational steps for power and control signal transmission through an electrical isolation element according to various embodiments.

FIG. 9 is another flow chart diagram illustrating the operational steps for power and control signal transmission through an electrical isolation element according to various embodiments.

DETAILED DESCRIPTION

This description provides examples, and is not intended to limit the scope, applicability or configuration of the invention. Rather, the ensuing description will provide those skilled in the art with an enabling description for implementing embodiments of the invention. Various changes may be made in the function and arrangement of elements.

Thus, various embodiments may omit, substitute, or add various procedures or components as appropriate. For instance, it should be appreciated that the methods may be performed in an order different than that described, and that various steps may be added, omitted or combined. Also, aspects and elements described with respect to certain embodiments may be combined in various other embodiments. It should also be appreciated that the following systems, methods, devices, and software may individually or collectively be components of a larger system, wherein other procedures may take precedence over or otherwise modify their application.

Methods, systems, and devices are described for a non-isolated dc-dc power converter that uses a single magnetic element and provides both a positive and a negative voltage output. The magnetic element, such as an inductor, is coupled with two or more switching modules that electrically switch the inductor to and from a voltage source, an inductor terminal, and/or a load. By electrically connecting and electrically isolating different components at various times, separate positive and negative voltage outputs are provided using the single inductor element. Switching may be controlled by a controller module, and a magnitude of the dc output voltage may be selected based on two or more resistors coupled with the controller module.

The term “switch” or “switch element,” as used herein, refers to an electrical circuit element that may have two electrical states, one of which substantially blocks current flow through the element and the other of which allows current flow through the element substantially unimpeded. Such switches may include, for example, rectifier diodes, transistors, relays, and thyristors.

With reference to FIG. 1, a block diagram of a system 100 of an embodiment is described. In this embodiment, system 100 provides for both positive voltage output and negative voltage output through a single magnetic element, namely inductor 105. In this embodiment, inductor 105 is used to provide a positive voltage to a first load 110, and to provide a negative voltage to a second load 115. Switching modules 120, 125, and 130 act to electrically couple components with other components, and to electrically isolate components from other components. These switching modules 120, 125, and 130, in various embodiments allow energy in the single inductor 105 to be stored and discharged to both positive output first load 110 and negative output second load 115 through coupling and isolating inductor 105 connection terminals with input power, ground, and the loads 110 and 115 in various sequences, as will be described in more detail below. In the embodiment of FIG. 1, a first output capacitor 135 is coupled with a connection terminal of the inductor 105 and provides a positive voltage to the first load 110. A second output capacitor 140 is coupled with the other terminal of the inductor 105 through switching module 130, and provides a negative voltage to the second load 115. Control module 145 controls the switching of the switching modules 120, 125, and 130. The components of the system 100 may, individually or collectively, include a number of discrete analog circuit elements. The components of the system 100 may also, individually or collectively, be implemented in whole or in part with one or more application specific integrated circuits (ASICs) adapted to perform some or all of the applicable functions in hardware. Alternatively, the functions may be performed by one or more other processing units (or cores), on one or more integrated circuits. In other embodiments, other types of integrated circuits may be used (e.g., controllers, voltage sensors, digital-to-analog or analog-to-digital converters) which may be programmed in any manner known in the art. p During a first operating state switching module 120 electrically couples the input voltage V_(IN) with a first input terminal on inductor 105. The second switching module 125, during the first operating state, isolates the first input terminal of inductor 105 from ground connection 150. Similarly, the third switching module 130 isolates the first input terminal of inductor 105 from the second load 115 and second output capacitor 140. During this first operating state, current ramps up in inductor 105, and the inductor 105 supplies a positive current to the first load 110. The inductor supplies a positive current to the first load in all operating states, assuming that there is sufficient energy stored in the inductor 105.

During a second operating state the first switching module 120 electrically isolates the inductor 105 from the input voltage V_(IN), and the third switching module 130 electrically isolates the inductor from the second load 115 and second output capacitor 140. The second switching module 125, in this operating state, electrically couples the inductor 105 with ground connection 150. The switching modules 120, 125, and 130 may use bi-directional voltage blocking switches to electrically connect and electrically isolate various components. During the second operating state the inductor 105 current ramps down.

During a third operating state the third switching module 130 electrically couples the inductor 105 with the second load 115 and second output capacitor 140. The second switching module 125 is switched to electrically isolate the inductor 105 from ground connection 135. The first switching module 120, in this operating state, electrically isolates the inductor 105 from voltage source V_(IN). During this third operating state, inductor 105 provides current to the second load 115 and second output capacitor 140, which is a negative output voltage load.

The control module 145, in various embodiments, may control the switching of switching modules 120, 125, and 130 to maintain the voltage at the first load 110 and first output capacitor 135, and second load 115 and second output capacitor 140, at preset levels. In one embodiment, the output voltage at the first load 110 and first output capacitor 135 may be selected to be maintained at a voltage of between 2.3 Volts and 5.5 Volts, and the output voltage at the second load 115 and second output capacitor 140 may be selected to be maintained at a voltage of between −5.0 Volts to −15 Volts. The selection of the output voltages at the controller 130 may be preset or user selectable.

In the embodiments of FIG. 1, the negative second load 115 is assumed to be relatively small in comparison to the positive first load 110. Another embodiment is illustrated in FIG. 2, in which a wider range of available voltages may be accommodated through the addition of switching modules 205 and 210 coupled with the positive connection terminal of inductor 105-a. In this example, circuit 200 contains the elements as described in FIG. 1, and has additional switching modules 205 and 210. A fourth switching module 205 is configured to electrically couple the inductor 105-a second terminal with a ground connection 215, and a fifth switching module 210 is configured to electrically couple the second terminal of the inductor 105-a with the first output load 110-a and first output capacitor 135-a. In this embodiment, single inductor 105-a has connection terminals that are coupled with switching modules 120-a, 125-a, 130-a, 205, and 210. Switching module 130-a is configured to electrically couple the first terminal of the inductor 105-a with the second (negative) output load 115-a and second output capacitor 140-a. Control module 145-a controls the switching of switching modules 120-a, 125-a, 130-a, 205, and 210 to allow energy in the single inductor 105-a to be stored and discharged to both positive output first load 110-a and negative output second load 115-a through coupling and isolating inductor 105-a connection terminals with input power, ground, and the loads 110-a and 115-a in various sequences, as will be described in more detail below. In this embodiment, control module 145-a is coupled with resistors 220 and 225, with the value of the resistors determining the output voltages at output loads 310 and 315. The control module 145-a and the capability to set output voltages based on resistors coupled with the control module 145-a will be described in additional detail below. The additional switching modules 205 and 210, relative to the embodiment of FIG. 1, enable greater control over the output loads 110-a and 115-a, as compared to the dc-dc converter of FIG. 1.

Similarly as described with respect to the circuit 100 of FIG. 1, the non-isolated dc-dc power converter of FIG. 2 may operate in a number of different operating states that allow energy in the single inductor 105-a to be stored and discharged to both positive output first load 110-a and negative output second load 115-a by coupling and isolating inductor 105-a connection terminals with input power, ground, and the loads 110-a and 115-a. During a first operating state switching module 120-a electrically couples the input voltage V_(IN) with a first input terminal on inductor 105-a. The second switching module 125-a, during the first operating state, isolates the first input terminal of inductor 105-a from ground connection 150-a. Similarly, the third switching module 130-a isolates the first input terminal of inductor 105-a from the second load 115-a and second output capacitor 140-a. The fourth switching module 205 is switched to couple the second input terminal of inductor 105-a with ground connection 215, and the fifth switching module 210 isolates the second input terminal of inductor 105-a from the first load 110-a and first output capacitor 135-a. During this operating state, current ramps up in inductor 105-a, and energy is stored in the inductor 105-a.

During a second operating state, switching modules 120-a, 125-a, and 130-a are switched so as to be in the same state as they were in the first operating state. The fourth switching module 205 isolates the second input terminal of inductor 105-a from ground connection 215. The fifth switching module 210, in this second operating state, electrically couples the second input terminal of inductor 105-a with the first load 110-a and first output capacitor 135-a. During this second operating state, the inductor 105-a supplies a positive current to the first load 110-a.

During a third operating state, the first switching module 120-a is switched to electrical isolate the inductor 105-a from the input voltage V_(IN), the third switching module 130-a is switched to electrically isolate the first input terminal of inductor 105-a from the second load 115-a and second output capacitor 140-a, the fourth switching module 205 is switched to couple the second input terminal of inductor 105-a to ground connection 215, and the fifth switching module 210 is switched to electrically isolate the second input terminal of inductor 105-a from the first load 110-a and first output capacitor 135-a. The second switching module 125-a, in this operating state, electrically couples the inductor 105-a with ground connection 150-a. During the third operating state, the inductor 105-a current ramps down.

During a fourth operating state, the third switching module 130-a electrically couples the inductor 105-a with the second load 115-a and second output capacitor 140-a. The second switching module 125-a is switched to electrically isolate the inductor 105-a from ground connection 135-a. The first switching module 120-a, in this operating sate, electrically isolates the inductor 105-a from voltage source V_(IN). The fourth switching module 205 is switched to isolate the second input terminal of inductor 105-a from ground connection 215, and the fifth switching module 210 is switched to isolate the second input terminal of inductor 105-a from the first load 110-a and first output capacitor 135-a. During this fourth operating state, inductor 105-a provides current to the second load 115-a and second output capacitor 140-a, which is a negative output voltage load.

The control module 145-a, may control the switching of switching modules 120-a, 125-a, 130-a, 205, and 210 to maintain the voltage at the first load 110-a and first output capacitor 135-a, and the voltage at the second load 115-a and second output capacitor 140-a, at preset levels. In one embodiment, the output voltage at the first load 110-a and first output capacitor 135-a may be selected to be maintained at a voltage of between 2.3 Volts and 5.5 Volts, and the output voltage at the second load 115-a and second output capacitor 140-a may be selected to be maintained at a voltage of between −5.0 Volts to −15 Volts.

FIG. 3 is a block diagram of a switching module 300 of an embodiment. The switching module 300 may be used, for example, as one or more of the switching modules 120, 130, 205, and 210 as described with respect to FIGS. 1 and 2. In the example of FIG. 3, the switching module includes a MOSFET 305 that is used as a switching element. The gate of the MOSFET 305 is coupled with the control module (e.g., control module 145 of FIG. 1 or control module 145-a of FIG. 2) that provides a signal to the switching module 300 to electrically couple, or electrically isolate, the components attached at opposite sides of the switching module 300. In other embodiments, the switching module 300 may include additional, or different components, and it is to be understood that the MOSFET 305 is provided in this example for purposes of illustration and discussion. In some embodiments, most of the switching modules of FIGS. 1 and 2 are implemented using switching module 300, with the control module providing signals to the gates of respective MOSFETS 305 to control the switching of the switching module 300. In other embodiments, various of the switching modules are implemented as bi-directional voltage blocking switches. FIG. 3A illustrates an exemplary bi-directional voltage blocking switch 350. In various embodiments, switching module 125 is different than the other switching modules, in that it provides bi-directional voltage blocking capability, such as implemented with switch 350 of FIG. 3A. The switch 350, in this example, includes first and second MOSFETS 355, 360, configured as shown to block voltage between the drain of MOSFET 355 and the drain of MOSFET 360.

In other embodiments, the control module is set to provide output voltages at preset levels for each of the positive and negative outputs. The control module in some of these embodiments may receive a value of the voltage that is output at each of the positive and negative outputs and adjust the duty cycle for various of the switching modules to achieve the desired voltage outputs. For example, control module 145-a of FIG. 2 may receive a signal representing the magnitude of the positive output voltage at output capacitor 135-a and first load 110-a. FIG. 4A illustrates a switching module 400 that may be used to couple the negative output with the inductor (e.g., switching module 130 of FIG. 1 or 130-a of FIG. 2), and also provide such a signal representing the magnitude of the voltage at the negative output and associated load (e.g., load 115, 115-a). In switching module 400, a switch 405 receives a signal from control module (e.g., control module 145-a of FIG. 2) that initiates a turn on or turn off of the switch 405. The switch 405 may be a MOSFET similarly as described with respect to FIG. 3, or any other suitable switching element. Switching module 400 also includes a voltage sensor 410. The voltage sensor 410 senses the voltage that is present at the node connecting the switch 405 and output capacitor and load relative to ground, or other reference voltage. FIG. 4B illustrates a switching module 450 that may be used to couple the positive output with the inductor (e.g., switching module 210 of FIG. 2), and also provide such a signal representing the magnitude of the voltage at the positive output and associated load (e.g., load 115-a). In switching module 440, a switch 455 receives a signal from the control module (e.g., control module 145-a of FIG. 2) that initiates a turn on or turn off of the switch 455. The switch 455 may be a MOSFET similarly as described with respect to FIG, 3, or any other suitable switching element. Switching module 450 also includes a voltage sensor 460. The voltage sensor 460 senses the voltage that is present at the node connecting the switch 455 and output capacitor and load relative to ground, or other reference voltage.

Thus, with reference to FIG. 2, if switching module 450 is used as the fifth switching module 210, the output of the voltage sensor 460 represents the magnitude of the positive voltage that is present across output capacitor 135-a. Similarly, if switching module 400 is used as the third switching module 130-a, the output of the voltage sensor 410 represents the magnitude of the negative voltage that is present across output capacitor 140-a. Switching modules 120-a, and 205 of FIG. 2 may be implemented, for example, using switching module 300 of FIG. 3, and switching module 125-a of FIG. 2 may be implemented, for example, using switching module 350 of FIG. 3A. With continued reference to FIGS, 4A and 4B, the output of the voltage sensor 410 (and voltage sensor 460 in embodiments that include switching module 210) is provided to the control module which may adjust the duty cycle for one or more of the switching modules in response thereto. The voltage sensor 410 and voltage sensor 460 may be any suitable voltage sensor as are well known. In the embodiments of FIGS. 1 and 2, such a switching module 400 may be required only for the switching modules 130 and 130-a, corresponding to the switching modules that are coupled with the negative output. Other switching modules may use the structure, for example, illustrated in FIG. 3.

As mentioned above, the control module controls the switching of the various switching modules that may be present in a non-isolated dc-dc voltage converter as described in various embodiments herein. The control modules that may be used in such applications may be preset with switching duty cycles for the switch modules of the voltage converter. In some embodiments, control modules may be programmed to generate positive and negative output voltages in the field through input or setting of one or more parameters. In one embodiment, illustrated in FIG. 5, a control module 500 may be set to control the switching modules to generate preset positive and negative voltages from the positive and negative outputs of the dc-dc voltage converter. The control module 500 may be used, for example, as the control module 145 of FIG. 1, or control module 145-a of FIG. 2. In this embodiment, resistor 220-a and 225-a may be coupled with control module 500, with the resistor values determining the target values for the positive and negative voltages from the positive and negative outputs of the dc-dc voltage converter. Thus, higher or lower values of resistance at resistors 220-a and 225-a will result in higher or lower target values for the positive and negative output voltages of the dc-dc voltage converter. For example, resistor 220-a may adjust the target output voltage value for the positive voltage output, and resistor 225-a may adjust the target output voltage value for the negative voltage output of the dc-dc voltage converter. The resistors 220-a and 225-a may, for example, be coupled with other resistors and capacitors within the control module 500 and adjust an RC time constant used in a timing module 510 for delaying one or more signals used to control duty cycles for the control signals provided from the timing module 510 to the switching modules.

In other embodiments, the control module may receive voltage level information related to the positive and negative outputs of the dc-dc voltage converter. FIG. 6 illustrates a control module 600 that receives voltage information from positive and negative voltage sensors. The control module 600 may be used, for example, as the control module 145 of FIG. 1, or control module 145-a of FIG. 2. The voltage information may be received from a voltage sensor of, for example, a switching module 400 as described with respect to FIG. 4. This voltage information, in combination with the resistor values for resistors 220-b and 225-b, may be used by a voltage adjustment module 605 to provide one or more signals to a timing module 610 to adjust the duty cycle for switching modules to attempt to maintain the positive and negative outputs of the dc-dc voltage converter at or near the programmed target values. The timing module 610 provides turn on and turn off signal information to each of the switch modules of the dc-dc voltage converter.

FIG. 7 illustrates an exemplary voltage adjustment module 605-a, according to an embodiment. The voltage adjustment module 605-a includes a positive error amplifier 705, and a negative error amplifier 710. Resistor 220-c may form a leg of a voltage divider for the negative error amplifier 710, and, similarly, resistor 225-c may form a leg of a voltage divider for the positive error amplifier 705. Each of the error amplifiers 705, 710, have a reference voltage V_(REF) input, and receive a sample of the output voltage at the positive and negative outputs, respectively. Each error amplifier 705, 710, then outputs a signal to the timing module that is indicative of the voltage level of the corresponding output. The timing module, as described above, may then actuate switching modules to achieve output voltages at the desired voltage levels. In some embodiments resistors 220-c and 225-c may be potentiometers, allowing for the adjustment of the target voltage at the positive and/or negative output through the adjustment of the potentiometer. In other embodiments, the resistors 220-c and 225-c may be selected during the design process to have values appropriate for providing target voltage levels at the positive and negative outputs.

With reference now to FIG. 8, a flow chart 800 of a method for providing output power to a first output load and a second output load is described. The steps of this method may be performed by one or more of the circuits described with respect to FIGS. 1-7. Initially, a first inductor terminal is electrically coupled with a power source, as indicated at block 805. The power source will act to store energy in the inductor that may be discharged at a later time through either the first inductor terminal to a negative voltage output, and/or to a second inductor terminal to a positive voltage output of the dc-dc voltage converter. At block 810, a first output load is electrically coupled with the second inductor connection terminal. The first output load thus receives a positive voltage output from the dc-dc voltage converter. The second output load is electrically isolated from the first inductor connection terminal while a first inductor connection terminal is electrically coupled with the power source, according to block 815. In such a manner, the negative voltage output is turned off during this operation. At block 820, the first inductor connection terminal is electrically isolated from the power source and electrically coupled with the second output load. The operation of block 820 is performed after electrically coupling the first inductor connection terminal with the power source. This allows the inductor to store energy before the second output load is electrically coupled with the first inductor connection, with the stored energy then provided to the second output load. The voltage at the second output load is a negative voltage from the first inductor connection that was previously connected to the power source. In such a manner, a single magnetic element provides both a positive and a negative voltage output.

With reference now to FIG. 9, a flow chart 900 of a method for providing output power to a first and a second output load is described. The steps of this method may be performed by one or more of the circuits described with respect to FIGS. 1-7. Initially, a first inductor terminal is electrically coupled with a power source, as indicated at block 905. At block 910, a first output load is electrically coupled with a second inductor connection terminal. A positive voltage is thus applied to the first output load. The second output load is electrically isolated from the first inductor connection terminal, while the first inductor connection terminal is electrically coupled with the power source, according to block 915. At block 920, the first inductor connection terminal is electrically isolated from the power source and electrically coupled with the second output load. Thus, the first inductor connection is moved from the power source to the second output load, providing a negative voltage to the second output load. The operation of block 820 is performed after electrically coupling the first inductor connection terminal with the power source. At block 925, the first inductor connection terminal is electrically isolated from the power source and the first inductor connection terminal is electrically coupled with a ground connection to ramp down current in the inductor. In such a manner, a single magnetic element provides both a positive and a negative voltage output.

While the above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather, as exemplifications or embodiments thereof. Many other variations are possible. For example, there are a wide variety of circuits that can benefit from the general approach to power and control signal transmission across an electrical isolation element. Circuits similar to the circuits shown but with polarity of the input or output reversed from that illustrated in the figures shall be considered embodiments of the subject invention. Circuits similar to those shown, but having coupled magnetic circuit elements with more than two windings and circuits with more than one output shall be considered embodiments of the subject invention. In many of the circuits shown there are series connected networks. The order of placement of circuit elements in series connected networks is inconsequential in the illustrations shown so that series networks in the illustrated circuits with circuit elements reversed or placed in an entirely different order within series connected networks are equivalent to the circuits illustrated and shall be considered embodiments of the subject invention. Also, some of the embodiments illustrated show N channel MOSFET switches, but the operation revealed and the benefits achieved can also be realized in circuits that implement the switches using P channel MOSFETs, combinations of N channel and P channel MOSFETs, IGBTs, JFETs, bipolar transistors, junction rectifiers, or schottky rectifiers, which should be considered embodiments of the disclosure.

These components may, individually or collectively, be implemented with one or more Application Specific Integrated Circuits (ASICs) adapted to perform some or all of the applicable functions in hardware. Alternatively, the functions may be performed by one or more other processing units (or cores), on one or more integrated circuits. In other embodiments, other types of integrated circuits may be used (e.g., Structured/Platform ASICs, Field Programmable Gate Arrays (FPGAs) and other Semi-Custom ICs), which may be programmed in any manner known in the art. The functions of each unit may also be implemented, in whole or in part, with instructions embodied in a memory, formatted to be executed by one or more general or application-specific processors.

It should be noted that the methods, systems and devices discussed above are intended merely to be examples. It must be stressed that various embodiments may omit, substitute, or add various procedures or components as appropriate. For instance, it should be appreciated that, in alternative embodiments, the methods may be performed in an order different from that described, and that various steps may be added, omitted or combined. Also, features described with respect to certain embodiments may be combined in various other embodiments. Different aspects and elements of the embodiments may be combined in a similar manner. Also, it should be emphasized that technology evolves and, thus, many of the elements are exemplary in nature and should not be interpreted to limit the scope of the invention.

Specific details are given in the description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, well-known circuits, processes, algorithms, structures, and techniques have been shown without unnecessary detail in order to avoid obscuring the embodiments.

Also, it is noted that the embodiments may be described as a process which is depicted as a flow diagram or block diagram. Although each may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process may have additional steps not included in the figure.

Having described several embodiments, it will be recognized by those of skill in the art that various modifications, alternative constructions, and equivalents may be used without departing from the spirit of the invention. For example, the above elements may merely be a component of a larger system, wherein other rules may take precedence over or otherwise modify the application of the invention. Also, a number of steps may be undertaken before, during, or after the above elements are considered. Accordingly, the above description should not be taken as limiting the scope of the invention. 

1. A power converter apparatus, comprising: a power source; a first switching module coupled with the power source; an inductor having a first connection terminal and a second connection terminal, the first connection terminal coupled with the first switching module; a first output terminal coupled with a first load; a second switching module coupled with the first switching module and the first connection terminal of the inductor; a second output terminal coupled with a second load; and a control module coupled with the first and second switching modules and configured to: switch the first switching module to electrically couple the first connection terminal of the inductor with the power source and supply a voltage of a first polarity at the first output terminal; switch the first switching module to electrically isolate the power source from the first connection terminal of the inductor; and switch, while the power source is electrically isolated from the first connection terminal, the second switching module so as to electrically couple the first connection terminal of the inductor with the second output terminal and thereby supply a voltage of a second polarity to the second output terminal.
 2. The apparatus of claim 1, wherein the control module is further configured to switch the second switching module to electrically isolate the second output terminal from the first connection terminal of the inductor while the first connection terminal of the inductor is electrically coupled with the power source.
 3. The apparatus of claim 1, further comprising: a third switching module coupled between the first input terminal of the inductor and a ground connection, and wherein the control module is further configured to switch the third switching module to electrically couple the first input terminal of the inductor with ground and switch the first and second switching modules to electrically isolate the first input terminal of the inductor from the power source and the second output terminal when the voltages at the first and second output terminals are at or near target values for the first and second output terminal voltages.
 4. The apparatus of claim 1, further comprising: a first output capacitor coupled between the second connection terminal of the inductor and a ground connection; and a second output capacitor coupled between the second switching module and a ground connection.
 5. The apparatus of claim 1, further comprising: a third switching module coupled between the second connection terminal of the inductor and the first output terminal; and wherein the control module is further configured to switch the third switching module to alternately electrically isolate or electrically couple the first output terminal and the second connection terminal of the inductor.
 6. The apparatus of claim 5, wherein the control module is further configured to: switch the third switching module to electrically isolate the first output terminal from the second connection terminal of the inductor; switch the second switching module to electrically couple the first connection terminal of the inductor with the second output terminal while the first output terminal is electrically isolated from the second connection terminal of the inductor; and switch the first switching module to electrically isolate the first connection terminal of the inductor from the power source while the power source is electrically isolated from the first connection terminal while the first output terminal is electrically isolated from the second connection terminal of the inductor and the first connection terminal of the inductor to the second output terminal.
 7. The apparatus of claim 1, wherein the control module is coupled with two or more resistors, and the control module is configured to control the switching of the modules based on the value of the resistors.
 8. The apparatus of claim 3, wherein the third switching module comprises a bi-directional voltage blocking switch.
 9. A method for providing power to a first and a second output load, comprising: electrically coupling a first inductor connection terminal with a power source; electrically coupling the first output load with a second inductor connection terminal; electrically isolating the second output load from the first inductor connection terminal while the first inductor connection terminal is electrically coupled with the power source; and after electrically coupling the first inductor connection terminal with the power source, electrically isolating the first inductor connection terminal from the power source and electrically coupling the first inductor connection terminal with the second output load thereby providing power to the second output load.
 10. The method of claim 9, further comprising: after electrically isolating the first inductor connection terminal from the power source and electrically coupling the first inductor connection terminal with the second output load, electrically isolating the second output load from the first inductor connection terminal and electrically coupling the first inductor connection terminal with the power source.
 11. The method of claim 9, further comprising: after coupling the first inductor connection terminal with the power source and before electrically coupling the first inductor connection terminal with the second output load, electrically isolating the first inductor connection terminal from the power source and electrically coupling the first inductor connection terminal with a ground connection.
 12. The method of claim 11, further comprising: after ramping down current in the inductor, electrically isolating the first inductor connection terminal from the ground connection and electrically coupling the first inductor connection terminal with the second output load.
 13. The method of claim 9, further comprising: after electrically coupling the first inductor connection terminal with the power source: electrically isolating the first inductor connection terminal from the power source, electrically isolating the second inductor connection terminal from the first output load, and electrically coupling the first inductor connection terminal with the second output load.
 14. The method of claim 9, wherein timing of the electrically coupling and electrically isolating steps is determined based on input to a controller module.
 15. The method of claim 14, wherein the timing is determined based on values of two or more resistors coupled with the controller module.
 16. An apparatus for providing power to a first and a second output load, comprising: means for electrically coupling a first inductor connection terminal with a power source; means for electrically coupling the first output load with a second inductor connection terminal; means for electrically isolating the second output load from the first inductor connection terminal while the first inductor connection terminal is electrically coupled with the power source; and means for electrically isolating the first inductor connection terminal from the power source and electrically coupling the first inductor connection terminal with the second output load after electrically coupling the first inductor connection terminal with the power source.
 17. The apparatus of claim 16, further comprising: means for electrically isolating the second output load from the first inductor connection terminal and electrically coupling the first inductor connection terminal with the power source after electrically isolating the first inductor connection terminal from the power source and electrically coupling the first inductor connection terminal with the second output load.
 18. The apparatus of claim 16, further comprising: means for electrically isolating the first inductor connection terminal from the power source and electrically coupling the first inductor connection terminal with a ground connection to ramp down current in the inductor after coupling the first inductor connection terminal with the power source and before electrically coupling the first inductor connection terminal with the second output load.
 19. The apparatus of claim 18, further comprising: means for electrically isolating the first inductor connection terminal from the ground connection and electrically coupling the first inductor connection terminal with the second output load after ramping down current in the inductor.
 20. The apparatus of claim 16, further comprising: controller means for controlling the timing of the electrically coupling and electrically isolating steps. 